1. Field of the Invention
This invention relates generally to nebulizers for delivering aerosolized medications for inhalation, and more particularly, for an improved portable nebulizer having a flow regulator enabling patients to deliver accurate amounts of aerosolized medications in substantially any setting.
2. Description of Related Art
Known prior art in nebulization of medications for hospital care, home care, and paramedical care consist of various systems, most of which are open and where the patient draws in medication and ambient air through a nebulizer, flex tube, T-piece and mouth piece. That is, a pneumatic device powered by a connecting tube to an air or an oxygen gas source.
The nebulizer units are commonly disposable and intended for single patient use only. They are further designed to break up liquid medication into 2 to 3 micron sized particles which are entrained in the stream of gas flow. This provides an aerosol for respiratory therapy in the treatment of chronic and/or acute pulmonary disorders or injuries.
The portability of known nebulizing devices has long been a problem and proposals have been made to make such devices more readily portable and/or adapted to be used in other circumstances.
Examples of prior art devices which attempted to provide portability to a nebulizer are shown in U.S. Pat. No. 4,257,415 to Rubin; U.S. Pat. No. 4,454,877 to Miller et al.; U.S. Pat. No. 4,582,054 to Ferrer, which relates to a portable breathing device; U.S. Pat. No. 4,949,715 to Brugger, which relates to a transportable inhalation apparatus; U.S. Pat. No. 4,955,371 to Zamba et al., which relates to a disposable inhalation activated aerosol device; U.S. Pat. No. 4,972,830 to Wong et al., which also relates to an inhalation device and method; U.S. Pat. No. 5,027,809 to Robinson, which provides an improved "peeper" for use with a known nebulizer; and U.S. Pat. No. 5,054,478 to Grychowski et al., which relates to a nebulizer for connection to a water supply, and directly to an oxygen tank.
Most of the prior art type devices are based upon Bernoulli's principle for the delivery of nebulized liquid medication. All of these standard devices require an external source of gas flow and pressure (the flow medium), in order to properly function, with the exception of the metered dose inhaler type using dry medication suspension. The prior art devices attempt to overcome the known problems of the portable gas source being bulky, heavy, cumbersome and usually requiring a stand with wheels, or some other type of transporting feature, such as a shoulder strap, because the portable gas sources weigh in at as much as fifteen pounds, or even more. And, although some of the above cited prior art devices overcame some of the problems with the known portable gas sources, they do not meet all the perceived and real needs of some of the more severely impaired patients, and do not meet today's need of accurate delivery of medication in substantially any setting.
All of the devices in the prior art use source gas units to drive or operate these devices, and are almost always interconnected by a length of tubing known as a standard oxygen tubing, and not by direct means. These known prior art devices require various types of adapters and/or connection means to secure or fix the interconnecting tubing between the source and the device before operation and delivery of medication will occur. However, these adapters are usually of a conical friction type fit and must be pressed into the tubing by hand, or threaded into a flow control device which is then attached to the source unit. Furthermore, they are usually constructed so that inadvertent disconnection or disruption can occur anywhere along the route of connection, thus interrupting the delivery of medication.
In today's hospital environment, many patients, after an acute medical event and intervention or diagnosis of a chronic condition, are prescribed supplemental oxygen flow for home use during recovery and/or rehabilitation. Because oxygen is now deemed a drug and its use monitored, physicians must write an order or prescription, before it is made available to the patient. Furthermore, standard hospital patient release protocols limit the amount of oxygen allowed for home use, to liter flows of less than four liters per minute (lpm), to avoid any inadvertent oxygen toxicity, with specific diagnosis being the only exception.
Prior and known specifications also expose the fact that to nebulize the most advantageous particle size for inhalation (2 to 3 microns in diameter), a sufficient source of gas flow, i.e., between 5 to 7 lpm must be available either from a large cylinder source, or a generation device such as a compressor, or the like, to enable known nebulizers to properly function.
Since most home use oxygen is supplied by low flow generating devices such as concentrators, compressors and the like, rather than large cylinders enabling high flows up to 15 lpm, these low flow home generating devices are limited to maximum flow capabilities of 4 lpm. Nevertheless, patients have to power their treatment devices via these modalities, thereby receiving a much less than optimum personally administered treatment.
Some patients are able to use metered dose inhalers (MDI), in that they have the inspiratory capacity/neuromotor-function to benefit from this type of device, and its pocket size availability. However, many more patients, because of physical impairments and/or lack of abilities, do not possess the necessary inspiratory capacity to be able to use known MDI devices. These patients, therefore, must be tethered to a source device in the home or elsewhere. Such source devices usually require electricity. Such devices diminish the mobility, recovery and rehabilitation of such patients, and do not always provide the necessary medical treatment regiment prescribed by the doctor. Still other devices require mandatory return to home or other places, such as clinics or hospitals, so that the patients may receive their next scheduled nebulized liquid treatment.
The portable nebulizer of the present invention overcomes many of the problems of the prior art devices by providing an easy to use and operate hand held device which provides accurately controlled nebulizer flow rates for a given patient, using known nebulizers, in substantially any setting.